[PATCH] glibc vDSO bits for ppc/ppc64 update
sjmunroe at us.ibm.com
Sat Nov 12 09:32:11 EST 2005
Benjamin Herrenschmidt <benh at kernel.crashing.org> wrote on 11/11/2005
> > Additional hp_timer_t is now declared as unsigned long long int
> > to match up with benh's get_tbfreq on 32 bit ppc. (ppc64 is already
> > 64 bit)
> I'm not sure having hp_timer_t be 64 bits on 32 bits libraries is the
> right thing to do. I suppose it's a matter of performances tradeoff. The
> fact that the vDSO __kernel_get_tbfreq() returns a long long doesn't
> force you to use a long long hp_timer_t, the vDSO doesn't have to return
> a value of type hp_timer_t :)
> I did that on the vDSO to avoid having to change the vDSO interface if
> we ever have to deal with >4Ghz time sources.
A 64-bit timebase is required to the use hp-timing for clock_gettime(
CLOCK_PROCESS_CPUTIME_ID, ) and clock_gettime(CLOCK_THREAD_CPUTIME_ID, ).
So 64-bit it is.
Steven J. Munroe
Linux on Power Toolchain Architect
IBM Corporation, Linux Technology Center
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